Methods for manufacturing a paint roller and component parts thereof

ABSTRACT

Described are methods of making a paint roller using an adhesive made from a compound of polypropylene and calcium carbonate having between 5% and 66% calcium carbonate by weight. Described are methods of making a paint roller using preformed strips or core material made from a compound of polypropylene and calcium carbonate having between 5% and 66% calcium carbonate by weight. Described are methods of making a paint roller using a composite cover material made from a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight. One or various compounds may be used to form portions of one or multiple components that make up the paint roller, including, for example, the thermoplastic strips, adhesives and/or the backing of a composite cover material. The materials can be assembled in a continuous manufacturing process.

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/435,946 filed May 5, 2009.

This application includes material which is subject to copyrightprotection. The copyright owner has no objection to the facsimilereproduction by anyone of the patent disclosure, as it appears in thePatent and Trademark Office files or records, but otherwise reserves allcopyright rights whatsoever.

FIELD OF THE INVENTION

This invention pertains to methods and apparatus for making paintrollers of the type used for applying paint to walls and the like. Morespecifically, the invention pertains to methods and apparatus for makingcomponent parts for use in a process of making a paint roller, andmethods and apparatus for making a paint roller.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings forming a part of this specification, andin which like reference characters are employed to designate like partsthroughout the same:

FIG. 1 is a diagrammatic representation of a paint roller manufacturingapparatus that can be used in accordance with an embodiment of thepresent invention.

FIG. 2 is a diagrammatic representation of an apparatus for forming acomposite paint roller cover having a compound backing in accordancewith an embodiment of the present invention.

FIG. 3 is a diagrammatic representation of a multi-strip laminate paintroller manufacturing apparatus that can be used in accordance with anembodiment of the present invention.

FIG. 4 is a diagrammatic representation of another paint rollermanufacturing apparatus that can be used in accordance with anembodiment of the present invention.

FIG. 5 is a diagrammatic representation of yet another paint rollermanufacturing apparatus that can be used in accordance with anembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION AND EMBODIMENTS THEREOF

FIG. 1 shows a diagrammatic representation of a paint rollermanufacturing apparatus 100. A strip of material 145 comprisingpolypropylene is wrapped helically about a mandrel 140 held on a base150. The mandrel may be cooled by a cooler (not shown). An adhesive 135comprising polypropylene is applied to an outer surface of the strip 145by applicator 130. A cover 125 is wrapped around the mandrel 150 overthe first strip 145 and the adhesive 135. A helical belt 120 driven byrollers 120 a, 120 b applies a compressive force on the cover materialand advances the tubular assembly 115 down the mandrel 150. A flyawaysaw 105 cuts the tubular assembly into lengths 110 that can be used, orcut and used to produce finished paint rollers.

Compound Adhesive

In an embodiment, the adhesive 135 is a compound of polypropylene andcalcium carbonate having between 5% and 50% calcium carbonate by weight.In an embodiment the adhesive compound comprises at least 25% but notmore than 45% calcium carbonate. In an embodiment the adhesive compoundcomprises at least 25% but not more than 33% calcium carbonate. In anembodiment, the calcium carbonate compounded with the polypropylene toform the compound adhesive 135 should be selected and/or processed to berelatively non-abrasive to the processing equipment.

In an embodiment, the applicator 130 applies a compound adhesive 135formed by a twin screw extruder sufficient for compounding the calciumcarbonate with polypropylene (not shown) from a supply of polypropyleneresin in pellet form and a supply of calcium carbonate. When using atwin screw extruder, the calcium carbonate should be relativelynon-abrasive to a extruder.

In an embodiment, the calcium carbonate compounded with thepolypropylene to form the compound adhesive 135 should be used in arelatively fine, powdered form. In an embodiment the calcium carbonatemay have a median particle size of 3 micrometers or less. In anembodiment, the calcium carbonate compounded with the polypropylene toform the compound adhesive 135 may be surface treated.

The cost by weigh of calcium carbonate is expected to be lower than thecost by weigh of polypropylene, thus the use of a compounded adhesive135 as described will reduce the cost of manufacturing paint rollers.

The adhesive 135 made from a compound of polypropylene and calciumcarbonate having between 5% and 50% calcium carbonate by weight isexpected to have higher thermal conductivity that an adhesive made frompolypropylene alone. Accordingly, an adhesive 135 made from a compoundof polypropylene and calcium carbonate having between 5% and 50% calciumcarbonate by weight is expected to cool and set faster than an adhesivemade from polypropylene alone. As a result of the higher thermalconductivity, when the apparatus 100 is operated using an adhesive 135made from a compound of polypropylene and calcium carbonate havingbetween 5% and 50% calcium carbonate by weight, it is expected that theapparatus will operate at higher overall throughput than it would whenusing an adhesive 135 comprising more than 95% polypropylene.

Compound Strip Material

In an embodiment, the strip 145 is made of a compound of polypropyleneand calcium carbonate having between 5% and 50% calcium carbonate byweight. In an embodiment the strip 145 comprises at least 25% but notmore than 45% calcium carbonate. In an embodiment the strip 145comprises at least 25% but not more than 33% calcium carbonate.

In an embodiment, the calcium carbonate compounded with thepolypropylene to form the strip 145 should be a relatively fine,powdered form of calcium carbonate. In an embodiment the calciumcarbonate compounded with the polypropylene to form the strip 145 shouldhave a median particle size of 3 micrometers or less. In an embodiment,the calcium carbonate compounded with the polypropylene to form thestrip 145 may be surface treated.

The cost by weigh of calcium carbonate is expected to be lower than thecost by weigh of polypropylene, thus the use of a strip 135 made from acompound of polypropylene and calcium carbonate will reduce the cost ofmanufacturing paint rollers made therewith.

The strip 145 made from a compound of polypropylene and calciumcarbonate having between 5% and 50% calcium carbonate by weight isexpected to have higher thermal conductivity that an adhesive made frompolypropylene alone. Because of the higher thermal conductivity using astrip 145 made from a compound of polypropylene and calcium carbonatehaving between 5% and 50% calcium carbonate by weight, rather than astrip 145 made from more than 95% polypropylene, it is anticipated thatthe adhesive 135 will set faster, and thus, apparatus 100 will operateat higher overall throughput than it would when using a strip 145comprising more than 95% polypropylene.

Cover Material

In an embodiment, the cover 125 has a fabric backing and a pile outersurface such as knitted or woven cover materials; such a fabric backingof the cover 125 comprises interstitial pores into which adhesive 135may flow, especially when compressed by the belt 120. In an embodiment,the cover is made from a microfiber material; such a microfiber cover125 also comprises interstitial pores into which adhesive 135 may flow,especially when compressed by the belt 120.

In an embodiment, the cover 125 has a pile or microfiber outer surfaceand a smooth or uniformly imprinted backing formed from polypropylene.

In an embodiment, the cover 125 has a pile or microfiber outer surfaceand a smooth or uniformly imprinted backing formed from a compound ofpolypropylene and calcium carbonate having between 5% and 50% calciumcarbonate by weight. In an embodiment the cover 125 comprises at least25% but not more than 45% calcium carbonate. In an embodiment the cover125 comprises at least 25% but not more than 33% calcium carbonate.

In an embodiment, the calcium carbonate compounded with thepolypropylene to form the backing of the cover 125 should be arelatively fine, powdered form of calcium carbonate. In an embodimentthe calcium carbonate compounded with the polypropylene to form thebacking of the cover 125 should have a median particle size of 3micrometers or less. In an embodiment, the calcium carbonate compoundedwith the polypropylene to form the backing of the cover 125 may besurface treated.

The cost by weigh of calcium carbonate is expected to be lower than thecost by weigh of polypropylene, thus the use of the backing of the cover125 made from a compound of polypropylene and calcium carbonate willreduce the cost of manufacturing paint rollers made therewith.

The backing of the cover 125 made from a compound of polypropylene andcalcium carbonate having between 5% and 50% calcium carbonate by weightis expected to have higher thermal conductivity that an adhesive madefrom polypropylene alone. Because of the higher thermal conductivityusing a cover 125 having a backing made from a compound of polypropyleneand calcium carbonate having between 5% and 50% calcium carbonate byweight, rather than a backing made from more than 95% polypropylene, itis anticipated that the adhesive 135 will set faster, and thus,apparatus 100 will operate at higher overall throughput than it wouldwhen using a cover 125 having a backing comprising more than 95%polypropylene.

Use of Compounded Materials

Apparatus 100 may be operated according to the present invention usingan adhesive 135 made of a compound of polypropylene and calciumcarbonate having between 5% and 50% calcium carbonate by weight; using astrip 145 made of a compound of polypropylene and calcium carbonatehaving between 5% and 50% calcium carbonate by weight; and/or using acover 125 having a backing made of a compound of polypropylene andcalcium carbonate having between 5% and 50% calcium carbonate by weight.When more than one component is made of a compound of polypropylene andcalcium carbonate having between 5% and 50% calcium carbonate by weight,the percentage of calcium carbonate used in the compound forming theadhesive 135, the strip 145 and the cover 125 backing may be the same,or may differ from one-another.

When compounding of polypropylene and calcium carbonate in any compoundof between 5% and 50% calcium carbonate by weight, the calcium carbonateis not expected to melt. As discussed above, the resulting compounds areexpected to have higher thermal conductivity. Variation in the amount ofcalcium carbonate are within the scope of the invention, and thus, itwill be apparent to one of skill in the art that to some degree thermalconductivity can be controlled, or a desired thermal conductivity orrange of thermal conductivity can be achieved by varying the percentageof calcium carbonate in the compound.

The compounds of polypropylene and calcium carbonate used in theadhesive 135, strip 145 and/or cover 125 are expected to have achieveother characteristics that, when compared to using polypropylene alone,are expected to include increased stiffness. Increased stiffness maygive a paint roller a firmer or stiffer feel, which may improve itsperformance as a paint roller. Moreover, in many cases, stiffer orfirmer paint rollers are sold at a higher price. It will be apparent toone of skill in the art that to some degree, stiffness can becontrolled, or a desired stiffness or range of stiffness can be achievedby varying the percentage of calcium carbonate in the compound.

FIG. 2 shows an apparatus 200 for forming the composite paint rollercover 250 having a compound backing. The roller 220 is urged toward theframe 230 by a spring, by gravity or by other means that will beapparent to persons skilled in the art. A layer of compound adhesive 210is dispensed by an applicator 205 onto a roller 220, and runs betweenthe roller 220 and a frame 230, such as a tenter frame, or between theroller 220 and another roller (not shown). The layer of compoundadhesive 210 dispensed onto roller 220 may be between 0.010″ and 0.020″.In an embodiment, the compound adhesive 210 is a compound ofpolypropylene and calcium carbonate having between 5% and 50% calciumcarbonate by weight. In an embodiment the adhesive compound comprises atleast 25% but not more than 45% calcium carbonate. In an embodiment theadhesive compound comprises at least 25% but not more than 33% calciumcarbonate. The calcium carbonate should be relatively non-abrasive tothe processing machinery.

The cover material 215 is advanced along the frame 205 with its pileside down, and moved beneath the roller 220. The cover material 215 mayhave a pile side and a fabric backing—the fabric backing being porousand having interstitial spaces sufficient to permit penetration of thecompound adhesive 210. As the cover material 215 and the layer ofcompound adhesive 210 pass between the roller 220 and the surface of theframe 230 they are urged together. The roller-side of the compoundadhesive 210 may be smoothed or uniformly imprinted (e.g., embossed) bythe roller 220 as it passed underneath, thus forming a uniform or smoothadhesive layer surface 225.

In an embodiment, the roller 220 applies a compressive force to urge thecompound adhesive 210 towards the cover material 215. In an embodiment,the compressive force is sufficient to force the compound adhesive 210into the interstitial spaces within the fabric backing of the covermaterial 215. The resulting composite sheet material 235 may be cut by acutter 240 to trim away any excess materials, and thus to form thecompound composite cover material 250 with a non-porous backing.

In an embodiment, the roller 220 may be heated or cooled.

In an embodiment, the apparatus comprises an applicator 205 that appliesa compound adhesive 210 formed by a twin screw extruder sufficient forcompounding calcium carbonate with polypropylene (not shown) from asupply of polypropylene resin in pellet form and a supply of calciumcarbonate. The calcium carbonate should be relatively non-abrasive tothe twin screw extruder.

The positioning and angular orientation of the applicator 205 may bevaried. In an embodiment, the applicator is angled between 30 degreesand 60 degrees from vertical and positioned within inches of the middleof the roller 220. In another embodiment the applicator 205 is within 30degrees (+/−) of vertical, and is positioned to dispense adhesive suchthat the adhesive layer 210 first makes contact on the upper half of theroller 220. In yet another embodiment, the applicator 205 is within 30degrees (+/−) of horizontal and is positioned to dispense adhesive suchthat the adhesive layer 210 first makes contact on the lower half of theroller 220. Variations in the angular orientation of the applicator 205,and its distance from and orientation around the roller are within thescope of the invention, and will be apparent to one skilled in the art.

FIG. 3 shows a paint roller manufacturing apparatus 300. A strip ofmaterial 345 comprising polypropylene is wrapped helically about amandrel 340 held on a base 350. The mandrel may be cooled by a cooler(not shown). A second strip of material 348 comprising polypropylene iswrapped helically about the first strip 345. An adhesive 335 comprisingpolypropylene is applied to an outer surface of the strips 345, 348 byapplicator 330. A cover 325 is also helically wrapped around the mandrel350 over the strips 345, 348 and the adhesive 335. A helical belt 320driven by rollers 320 a, 320 b applies a compressive force on the covermaterial and advances the tubular assembly 310 down the mandrel 350. Aflyaway saw 305 may cut the tubular assembly 310 into lengths (notshown) that can be used, or further cut and used to produce finishedpaint rollers.

In an embodiment, the applicator 330 applies a compound adhesive 335formed by a twin screw extruder sufficient for compounding the calciumcarbonate with polypropylene (not shown) from a supply of polypropyleneresin in pellet form and a supply of calcium carbonate. When using atwin screw extruder, the calcium carbonate should be relativelynon-abrasive to a extruder.

Apparatus 300 may be operated according to the present invention usingan adhesive 335 made of a compound of polypropylene and calciumcarbonate having between 5% and 50% calcium carbonate by weight; using astrip 345 made of a compound of polypropylene and calcium carbonatehaving between 5% and 50% calcium carbonate by weight; using a secondstrip 348 made of a compound of polypropylene and calcium carbonatehaving between 5% and 50% calcium carbonate by weight; and/or using acover 325 having a backing made of a compound of polypropylene andcalcium carbonate having between 5% and 50% calcium carbonate by weight.When more than one component is made of a compound of polypropylene andcalcium carbonate having between 5% and 50% calcium carbonate by weight,the percentage of calcium carbonate used in the compound forming theadhesive 335, the strip 345, the second strip 348 and the cover 325backing may be the same, or may differ from one-another.

Variation in the amount of calcium carbonate are within the scope of theinvention, and thus, it will be apparent to one of skill in the art thatto some degree thermal conductivity can be controlled, or a desiredthermal conductivity or range of thermal conductivity can be achieved byvarying the percentage of calcium carbonate in one or more of thecompounds. It will be apparent to one of skill in the art that to somedegree, stiffness can be controlled, or a desired stiffness or range ofstiffness can be achieved by varying the percentage of calcium carbonatein these compounds as well.

FIG. 4 shows a paint roller manufacturing apparatus 400. A strip ofmaterial 448 comprising polypropylene is wrapped helically about amandrel 440 held on a base 450. The mandrel may be cooled by a cooler(not shown). A second strip of material 445 comprising polypropylene iswrapped helically about the first strip 448. The heaters 460, 455 whichmay employ heating elements or heat by open flame, heat the outersurface (vis-à-vis the wrapping about the mandrel) of strips 448, 445respectively. The heat produced by the heaters 460 is sufficient tocause the outer surface of the strips 448, 445 to become tacky, or toliquefy, or to become molten. (Although shown diagrammatically at adistance from the mandrel, in an embodiment, the heaters 460, 455 shouldbe placed as close as practicable to the point where the strips 448, 445contact the mandrel.) A cover 415 is also helically wrapped around themandrel 440 over the outer surface of the second strip 445. A helicalbelt drive 420 applies an inwardly compressive force on the covermaterial 415 and advances the assembly down the mandrel 440. A flyawaysaw 405 may cut the assembly into lengths (not shown) that can be used,or further cut and used to produce finished paint rollers.

Apparatus 400 may be operated according to the present invention using astrip 448 made of a compound of polypropylene and calcium carbonatehaving between 5% and 50% calcium carbonate by weight; using a secondstrip 445 made of a compound of polypropylene and calcium carbonatehaving between 5% and 50% calcium carbonate by weight; and/or using acover 415 having a backing made of a compound of polypropylene andcalcium carbonate having between 5% and 50% calcium carbonate by weight.When more than one component is made of a compound of polypropylene andcalcium carbonate having between 5% and 50% calcium carbonate by weight,the percentage of calcium carbonate used in the compound forming thestrips 448, 445 and the cover 415 backing may be the same, or may differfrom one-another.

Variation in the amount of calcium carbonate are within the scope of theinvention, and thus, it will be apparent to one of skill in the art thatto some degree thermal conductivity can be controlled, or a desiredthermal conductivity or range of thermal conductivity can be achieved byvarying the percentage of calcium carbonate in one or more of thecompounds. It will be apparent to one of skill in the art that to somedegree, stiffness can be controlled, or a desired stiffness or range ofstiffness can be achieved by varying the percentage of calcium carbonatein these compounds as well.

FIG. 5 shows an apparatus 500 suitable for making paint rollers with apreformed core. The apparatus 500 comprises a rotating mandrel 510, acarriage 560 running on a stationary track 570 and supporting a covermaterial guide 550, and a heater 530. A preformed core 540 comprisingpolypropylene is placed about the mandrel 510. The heater 530 isactivated, thereby heat softening the outer surface of the preformedcore in an amount sufficient to bond to the backing of the cover 520.The cover 520 is wrapped helically about the core by the rotation of themandrel and the movement of the carriage 560. The rotation of themandrel 510 and the movement of the carriage 560 are such that the cover520 is wrapped about substantially all of the preformed core 540.

Apparatus 500 may be operated according to the present invention using apreformed core 540 made of a compound of polypropylene and calciumcarbonate having between 5% and 50% calcium carbonate by weight; and/orusing a cover 520 having a backing made of a compound of polypropyleneand calcium carbonate having between 5% and 50% calcium carbonate byweight. When more than one component is made of a compound ofpolypropylene and calcium carbonate having between 5% and 50% calciumcarbonate by weight, the percentage of calcium carbonate used in thecompound forming the core 540 and the cover 520 backing may be the same,or may differ from one-another.

Variation in the amount of calcium carbonate are within the scope of theinvention, and thus, it will be apparent to one of skill in the art thatto some degree thermal conductivity can be controlled, or a desiredthermal conductivity or range of thermal conductivity can be achieved byvarying the percentage of calcium carbonate in one or more of thecompounds. It will be apparent to one of skill in the art that to somedegree, stiffness can be controlled, or a desired stiffness or range ofstiffness can be achieved by varying the percentage of calcium carbonatein these compounds as well.

It is possible, without departing from the invention, to use a compoundof polypropylene and calcium carbonate having between 5% and 50% calciumcarbonate by weight in lieu of polypropylene in making paint rollers. Inlight of this disclosure, other methods for the manufacture of the samewill be apparent to persons of skill in the art.

Benefits of certain embodiments of the instant invention include:control of thermal conductivity in the component materials leading tofaster throughput and/or faster set times; and control of materialcharacteristics such as stiffness for manufacture of harder, moreexpensive paint rollers.

The above embodiments and preferences are illustrative of the presentinvention. It is neither necessary, nor intended for this patent tooutline or define every possible combination or embodiment. The inventorhas disclosed sufficient information to permit one skilled in the art topractice at least one embodiment of the invention, and has disclosed theways the inventor now believes are the best ways to practice theinvention. The above description and drawings are merely illustrative ofthe present invention and that changes in components, structure andprocedure are possible without departing from the scope of the presentinvention as defined in the following claims.

Illustrative Embodiments Shown in the Figures

In one embodiment, the invention is a method of making a paint roller. Astrip of material is helically wound around a mandrel so as to form ahelically wound strip. The strip is formed from a compound ofpolypropylene and calcium carbonate having between 5% and 50% calciumcarbonate by weight. The wound strip is advanced along the mandrel. Alayer of adhesive is applied onto an outer surface of the wound strip. Astrip of cover material then is helically wrapped about the wound stripand over the layer of adhesive, thereby bonding the strip of covermaterial to the wound strip for forming the paint roller.

In another embodiment, the invention is method of making a paint roller.A strip of material is helically wound around a mandrel so as to form ahelically wound strip. The wound strip is advanced along the mandrel. Anadhesive is compounded from polypropylene and calcium carbonate. Thecompound comprises between 5% and 50% calcium carbonate by weight. Thelayer of adhesive is applied onto an outer surface of the wound strip. Astrip of cover material then is helically wrapped about the wound stripand over the layer of adhesive, thereby bonding the strip of covermaterial to the wound strip for forming the paint roller.

In another embodiment, the invention is method of making a paint roller.A strip of material helically wound around a mandrel so as to form ahelically wound strip. The strip is formed from a compound ofpolypropylene and calcium carbonate having between 5% and 50% calciumcarbonate by weight. The wound strip is advanced along the mandrel. Anadhesive is compounded from polypropylene and calcium carbonate. Thecompound comprises between 5% and 50% calcium carbonate by weight. Thelayer of adhesive is applied onto an outer surface of the wound strip. Astrip of cover material then is helically wrapped about the wound stripand over the layer of adhesive, thereby bonding the strip of covermaterial to the wound strip for forming the paint roller.

In another embodiment, the invention is a method for continuouslyproducing a multi-strip laminate paint roller. An inner strip and anouter strip of material is helically advanced about a mandrel in offsetrelation. At least one of the strips is formed from a compound ofpolypropylene and calcium carbonate having between 5% and 50% calciumcarbonate by weight. A layer of adhesive is applied between the twostrips and on the outer surface of the outer strip. Prior to permittingthe layer of liquid polypropylene to harden and set, a cover is wrappedaround the outer strip and a compressing force is applied upon the coverurging the cover and the two strips toward the mandrel, thereby creatingthe continuous laminated paint roller.

In another embodiment, the invention is a method for continuouslyproducing a multi-strip laminate paint roller. An inner strip and anouter strip of material is helically advanced about a mandrel in offsetrelation. An adhesive material is compounded from polypropylene andcalcium carbonate, the compound comprising between 5% and 50% calciumcarbonate by weight. The adhesive material is applied between the twostrips and on the outer surface of the outer strip. Prior to permittingthe adhesive material to harden and set, a cover is wrapped around theouter strip and a compressing force is applied upon the cover urging thecover and the two strips toward the mandrel, thereby creating thecontinuous laminated paint roller.

In another embodiment, the invention is a method for continuouslyproducing a multi-strip laminate paint roller. An inner strip and anouter strip of material is helically advanced about a mandrel in offsetrelation, at least one of the strips being formed from a compound ofpolypropylene and calcium carbonate having between 5% and 50% calciumcarbonate by weight. An adhesive material is compounded frompolypropylene and calcium carbonate. The compound comprises between 5%and 50% calcium carbonate by weight. The adhesive material is appliedbetween the two strips and on the outer surface of the outer strip.Prior to permitting the layer of liquid polypropylene to harden and set,a cover is wrapped around the outer strip and a compressing force isapplied upon the cover urging the cover and the two strips toward themandrel, thereby creating the continuous laminated paint roller.

In another embodiment, the invention is a method of making a compositecover material. A first width of pile material is advanced. The pilematerial has a pile side and a fabric backing, wherein the fabricbacking is porous, having interstitial spaces or gaps. An adhesive iscompounded from polypropylene and calcium carbonate. The compoundcomprises between 5% and 50% calcium carbonate by weight. A layer of theadhesive is applied to the fabric backing of the pile material. Theadhesive layer is allowed to set to form a composite sheet materialhaving a pile side and a non-porous backing. The composite sheetmaterial is longitudinally cut to form one or more strips of compositecover material in a second width. The formed composite cover materialhas an inner surface and an outer surface, the outer surface comprisinga pile, and the inner surface comprising a non-porous layer bondedthereto.

In another embodiment, the invention is a method of making a paintroller having one or more materials making up its core. An adhesivematerial is compounded from polypropylene and calcium carbonate. Thecompound comprises between 5% and 50% calcium carbonate by weight. Theadhesive material is applied between a cover material and one or morematerials making up the paint roller core. The adhesive material ispermitted to harden and set, thereby creating the paint roller.

In another embodiment, the invention is a method of making a laminatedpaint roller. A strip comprising polypropylene is helically wound arounda mandrel so as to form a helically wound strip, the strip having anouter surface. The wound strip is helically advanced along the mandrel.A layer of adhesive comprising polypropylene is applied onto the outersurface of the wound strip. A strip of composite cover material is thenwrapped about the wound strip and over the layer of adhesive. Thecomposite cover material is formed by method comprising the followingsteps. A width of porous pile material is provided having a pile sideand an fabric underside. The width of pile material is advanced with thefabric underside facing up. A backing layer is compounded frompolypropylene and calcium carbonate, the compound comprising between 5%and 50% calcium carbonate by weight. The backing layer is applied on thefabric underside of the advancing width of pile material so that thelayer has one side that is in contact with the fabric underside of theadvancing material and an other side that is not in contact with theadvancing pile material, the layer being in molten form when it isapplied. A compressive force is applied to the other side of the layerbefore the layer hardens and sets, to smooth the other side of the layerof polypropylene, and to urge the layer and the fabric underside of thepile material together, thereby forming a composite material having asmooth or uniformly imprinted non-porous side and a pile side, andwherein the pile is held fast on the composite material. The width ofcomposite material is cut into a strip once the backing layer is nolonger in molten form, thereby forming a composite cover material havingan inner surface comprising a smooth or uniformly imprinted non-porouspolypropylene side and a pile side. The composite cover materialproduced by the method described above is then used to form a laminatedpain roller. A compressive force is applied from without the compositecover material to urge the composite cover material, the layer ofadhesive and strip of non-porous polypropylene material together,thereby laminating the smooth inner surface of the composite covermaterial to the outer surface of the non-porous polypropylene strip.

In another embodiment, the invention is a method of making a laminatedpaint roller. An inner strip of thermoplastic material is helicallyaround a mandrel so as to form a helically wound inner strip, the innerstrip having an outer surface. A second strip of thermoplastic materialis helically wound around a mandrel in offset relation to the innerstrip, so as to form a helically wound second strip, the second striphaving an inner surface and an outer surface. The wound inner and secondstrips are advanced along the mandrel. An adhesive is compounded frompolypropylene and calcium carbonate, the compound comprising between 5%and 50% calcium carbonate by weight. A layer of the adhesive is appliedonto the outer surface of the wound inner strip and the outer surface ofthe wound second strip. A strip of composite cover material is thenwrapped about the wound second strip and over the layer of adhesiveapplied to the wound second strip. The composite cover material has aninner surface and an outer surface, the outer surface comprising a pilefabric, and the inner surface comprising a smooth generally non-porousbacking comprising polypropylene. A compressive force is then appliedfrom without the composite cover material to urge the composite covermaterial, the layer of adhesive and inner and second strips together,thereby laminating the inner surface of the composite cover material tothe outer surface of the second strip and laminating the inner surfaceof the second strip to the outer surface of the inner strip.

In another embodiment, the invention is a method for continuouslyproducing a multi-strip laminate paint roller. An inner strip and anouter strip of material is helically advanced about a mandrel in offsetrelation. At least one of the strips is formed from a compound ofpolypropylene and calcium carbonate having between 5% and 50% calciumcarbonate by weight. The inner strip and the outer strip have an outersurface facing away from the mandrel. The outer surface of the inner andouter strips is heated to cause a layer of the outer surface of thestrips to become liquefied. Prior to permitting the liquefied layers toharden and set, a cover around is wrapped around the outer strip and acompressing force is applied upon the cover urging the cover and the twostrips toward the mandrel, thereby creating the continuous laminatedpaint roller.

In another embodiment, the invention is a cold core method of making apaint roller from a cold, hard, preformed hollow core of thermoplasticmaterial of a predetermined length in which the cold hard hollow coreand its associated cover are forged together to form a single unitarybody. A cold hard hollow core is provided. The cold hard hollow core isformed from a compound of polypropylene and calcium carbonate havingbetween 5% and 50% calcium carbonate by weight. A mandrel having anexternal diameter is provided. The mandrel slidably receives and makescontact with the cold hard hollow core. The cold hard hollow core isrotated. The exterior surface of the cold hard hollow thermoplasticrotating core is heated, by application of a single source of heat, to atemperature high enough to cause subsequently applied cover to adhere tosaid exterior surface. A cover is then to the heated exterior surface ofthe cold hard hollow thermoplastic core, thereby bonding the cover tothe heated exterior surface thereof, and forming a paint roller.

Further Observations

In experimenting with various ratios and materials, several furtherobservations have been made, and the inventions of such furtherobservations and additional embodiments are hereinafter presented, inaddition to those discussed above. Polypropylene identified as 3462-US,4920WZ-US and 6823MZ-US from Total Petrochemicals of Houston, Tex. wasused for experimentation. MFI reported herein for the polypropyleneresin is as understood from Total Petrochemicals literature.

Calcium Carbonate

The use of non-refined calcium carbonate in combination withpolypropylene, e.g., calcium carbonate that has not been surfacetreated, adds strength to the resulting paint roller product whencompared to a combination of refined calcium carbonate in combinationwith polypropylene. Thus, in an embodiment, the calcium carbonatecompounded with the polypropylene to form the compound adhesive 135(FIG. 1) may be a non-refined calcium carbonate. In an embodiment, thenon-refined calcium carbonate is used in a relatively fine, powderedform. In an embodiment the calcium carbonate may have a median particlesize of 3 micrometers or less.

In an embodiment, a twin screw extruder (not shown) may be used tocompound non-refined calcium carbonate and polypropylene together toform the compound adhesive 135. The twin screw extruder may accept asupply of polypropylene resin in pellet form and a separate supply ofcalcium carbonate.

Ratio and Composition of Compound Adhesive

Experimentation was performed concerning the ratio of calciumcarbonate—a ratio earlier thought to be preferred between 5% and 50%calcium carbonate by weight. As discussed above, the cost by weigh ofcalcium carbonate is generally lower than the cost by weigh ofpolypropylene, thus, the raw material cost of a compounded adhesive willbe reduced as the ratio of calcium carbonate rises. Typically, today,the cost of polypropylene resin may be $0.64 per pound, while the costof appropriate calcium carbonate may be $0.09 per pound. Using thosetypical costs, the raw materials required to make a compounded adhesivecomprising 5% calcium carbonate by weight is approximately $0.6125 perpound; the raw materials required to make a compounded adhesivecomprising 50% calcium carbonate by weight is approximately $0.365 perpound; and the raw materials required to make a compounded adhesivecomprising 60% calcium carbonate by weight is approximately $0.31 perpound. While the process of compounding the materials itself has a cost,the large factors in savings are: (i) the disparity between the cost ofthe polypropylene resin and the calcium carbonate; and (ii) thepercentages of calcium carbonate that can be used.

Experimentation was performed and acceptable results were found using acompounded adhesive 135 (see FIG. 1) made from polypropylene resin withapproximately 60% calcium carbonate by weight. In an embodiment,adhesive 135 is a compound of polypropylene and calcium carbonate havingbetween 50% and 66% calcium carbonate by weight. In an embodiment anadhesive compound 135 comprises at least 55% but not more than 65%calcium carbonate. In an embodiment an adhesive compound 135 is acompound of polypropylene and calcium carbonate having approximately 60%calcium carbonate by weight.

Experimentation was performed and acceptable results were found using acompounded adhesive 335 (see FIG. 3) made from polypropylene resin withapproximately 56% calcium carbonate by weight. In an embodiment, anadhesive 335 is a compound of polypropylene and calcium carbonate havingat least 50%, but less than 60% calcium carbonate by weight. In anembodiment an adhesive compound 335 is a compound of polypropylene andcalcium carbonate having approximately 56% calcium carbonate by weight.

Polypropylene resin 6823MZ-US in pellet form used to create adhesivefirst used for the further testing had a melt flow index (“MFI”) ofapproximately 32. For the further testing, the 32 MFI resin wascompounded with a 60% mixture of calcium carbonate to form the compoundadhesive 135. The resulting compound adhesive 135 had an MFI ofapproximately 14.4. Although the compound adhesive could be extrudedthrough applicator 130, the low MFI appeared to cause the extruder tostruggle, and the extruded material was highly viscous. The paintrollers resulting from the foregoing compound appeared to besubstantially stronger when non-refined calcium carbonate was usedrather than surface treated calcium carbonate. When the same 32 MFIresin was compounded with the same 60% mixture of calcium carbonate toform the compound adhesive 335 (see FIG. 3), it appeared that the MFI ofthe compound adhesive 335 was too high to permit a smooth flow from theapplicator 330.

Polypropylene resin 4920WZ-US was tried. Polypropylene resin 4920WZ-USin pellet form used to create adhesive next used for the further testinghad a melt flow index (“MFI”) of approximately 105. For the next test,the 105 MFI resin was compounded with a 60% mixture of calcium carbonateto form the compound adhesive 135. The resulting compound adhesive 135had an MFI of approximately 28.8. Using the 105 MFI resin, the compoundadhesive 135 was extruded through applicator 130 without substantialstress on the extruder as the compounded adhesive 135 was of appropriateviscosity for use with the applicator 130. Again, the paint rollersresulting from the foregoing compound was substantially stronger whennon-refined calcium carbonate was used rather than surface treatedcalcium carbonate. When the same 105 MFI resin was compounded with thesame 60% mixture of calcium carbonate to form the compound adhesive 335(see FIG. 3), it again appeared that the MFI was too high to permit asmooth flow from the applicator 330.

As the vendor did not have polypropylene resin available with an MFIhigher than 105, for the following test, the 105 MFI resin wascompounded with a 56% mixture of calcium carbonate to form the compoundadhesive 335. The resulting compound adhesive 335 had an MFI ofapproximately 32. Using the 105 MFI resin, the compound adhesive 335 wasextruded through applicator 330 without substantial stress on theextruder as the compounded adhesive 335 was of appropriate viscosity foruse with the applicator 330. As before, the paint rollers resulting fromthe foregoing compound appeared to be substantially stronger whennon-refined calcium carbonate was used rather than surface treatedcalcium carbonate. As an alternative to reducing ratio of calciumcarbonate to 56%, the use of a polypropylene resin having a higher MFI,such as an MFI of approximately 120, with 60% calcium carbonate wouldhave achieved acceptable results.

Composition of Strips

As with composite adhesives 135, 335, strip material 145, 345, 348, 445,448 can be manufactured using a compound of polypropylene and calciumcarbonate. In an embodiment, a strip 145, 345, 348, 445, 448 is cutlengthwise from a sheet material (not shown) that is manufactured usinga compound of polypropylene and calcium carbonate. In an embodiment, thethickness of the sheet material is determined by successive rollers.Because rollers are used to control thickness, the MFI of thepolypropylene/calcium carbonate compound may be substantially lower thanthat of the MFI required for use a compound adhesives 135, 335. In anembodiment, 4.1 MFI polypropylene resin 3462-US is compounded withapproximate 60% by weight of calcium carbonate. The resultingpolypropylene/calcium carbonate compound, having an MFI of approximately2, can be run through successive rollers to reach a desired thickness.Almost any desired strip thickness can be attained. In an embodiment, asheet of polypropylene/calcium carbonate compound material havingthickness of approximately 10 mil, 15 mil, 20 mil or 25 mil can be cutlongitudinally into one or more strip 145, 345, 348, 445, 448.

In an embodiment, the calcium carbonate used in manufacturing sheetmaterial which can be cut into strips is non-refined calcium carbonate.

Composite Cover Material

Returning to FIG. 2, an apparatus 200 is shown for forming the compositepaint roller cover 250 having a compound backing. A layer of compoundadhesive 210 is dispensed by an applicator 205. The layer of compoundadhesive 210 dispensed may be dispensed onto roller 220 or directly ontocover material 215. In an embodiment, the layer of compound adhesive 210is between 0.010″ and 0.020″. In an embodiment, the compound adhesive210 is a compound of polypropylene and calcium carbonate having at least50%, and not more than 66% calcium carbonate by weight. The MFI ofpolypropylene/calcium carbonate compound the may be varied by changingusing a polypropylene resin having a higher or lower MFI, as well as byvarying the ratio of calcium carbonate. Using polypropylene resin havinga higher MFI will cause the polypropylene/calcium carbonate compound tohave a higher MFI when using the same ratio of calcium carbonate.Similarly, the MFI of the resulting compound can be lowered by reducingthe percentage of calcium carbonate used in the polypropylene/calciumcarbonate compound. In view of the foregoing, it will be apparent to oneof skill in the art how to the MFI of polypropylene/calcium carbonatecompound layer 210 can be varied so as to permit it to be dispensedappropriately by an applicator 205.

In an embodiment, the cover material 215 has a pile side and a fabricbacking—the fabric backing being porous and having interstitial spacessufficient to permit penetration of compound adhesive 210. In anembodiment, the compound adhesive 210 has an MFI higher than 2. In anembodiment, the compound adhesive 210 has an MFI between 14 and 105. Inan embodiment, an MFI of in or around the mid 70's is desired to permitthe compound 210 to properly permeate the fabric backing of the covermaterial 215. To obtain compound adhesive 210 having an MFI in or aroundthe mid-70's 105 MFI polypropylene resin is compounded with 25% calciumcarbonate by weight.

In an embodiment, the apparatus comprises an applicator 205 that appliesa compound adhesive 210 formed by a twin screw extruder sufficient forcompounding calcium carbonate with polypropylene (not shown) from asupply of polypropylene resin in pellet form and a supply of calciumcarbonate to produce a compound that includes at least 50% calciumcarbonate by weight.

Illustrative Paint Rollers

Returning to FIG. 1, in an embodiment, a strip 145 comprisespolypropylene, and has a thickness of between 10 mil and 40 mil. In anembodiment, the strip 145 is approximately 10 mil, 15 mil, 20 mil or 25mil thick. In an embodiment, the strip 145 may be of another suitablethickness.

In an embodiment, the strip 145 is made from a polypropylene/calciumcarbonate compound comprising at least 50%, but not more than 66%calcium carbonate by weight. In an embodiment, the strip 145 is madefrom a polypropylene/calcium carbonate compound comprising approximately60% calcium carbonate by weight. The strip 145 made from apolypropylene/calcium carbonate compound comprising at least 50% calciumcarbonate by weight, is expected to have higher thermal conductivitythan a strip made from polypropylene alone, or than a strip made from apolypropylene/calcium carbonate compound comprising less than 50%calcium carbonate by weight. Because of the higher thermal conductivityusing a strip 145 made from a compound of polypropylene and calciumcarbonate comprising at least 50% calcium carbonate by weight, it isanticipated that the adhesive 135 will set faster, and thus, apparatus100 will operate at higher overall throughput than it would when using astrip 145 comprising more than 50% polypropylene.

In an embodiment, adhesive 135 comprises polypropylene, and is appliedin a layer having a thickness of between 10 mil and 40 mil. In anembodiment, the layer of adhesive 135 is approximately 10 mil, 15 mil,20 mil or 25 mil thick. In an embodiment, the layer of adhesive 135 isanother suitable thickness.

In an embodiment, the adhesive 135 is made from a polypropylene/calciumcarbonate compound comprising at least 50%, but not more than 66%calcium carbonate by weight. In an embodiment, the adhesive 135 is madefrom a polypropylene/calcium carbonate compound comprising approximately60% calcium carbonate by weight. The adhesive 135 made from apolypropylene/calcium carbonate compound comprising at least 50% calciumcarbonate by weight, is expected to have higher thermal conductivitythan an adhesive made from polypropylene alone, or than an adhesive madefrom a polypropylene/calcium carbonate compound comprising less than 50%calcium carbonate by weight. Because of the higher thermal conductivityusing an adhesive 135 made from a compound of polypropylene and calciumcarbonate comprising at least 50% calcium carbonate by weight, it isanticipated that it will set faster, and thus, apparatus 100 willoperate at higher overall throughput than it would when using anadhesive 135 comprising more than 50% polypropylene.

In an embodiment, the backing of composite cover 125 comprisespolypropylene, and the backing comprising polypropylene is in a layerhaving a thickness of between 10 mil and 40 mil. In an embodiment, thebacking layer of the composite cover material 125 is approximately 10mil, 15 mil, 20 mil or 25 mil thick. In an embodiment, the backing ofthe composite cover material 125 is another suitable thickness.

In an embodiment, the backing of the composite cover material 125 isformed from a polypropylene/calcium carbonate compound comprising atleast 50%, but not more than 66% calcium carbonate by weight. In anembodiment, the backing of the composite cover material 125 is formedfrom a polypropylene/calcium carbonate compound comprising approximately60% calcium carbonate by weight. The backing of the composite covermaterial 125 formed from a polypropylene/calcium carbonate compoundcomprising at least 50% calcium carbonate by weight, is expected to havehigher thermal conductivity than a backing made from polypropylenealone, or than a backing made from a polypropylene/calcium carbonatecompound comprising less than 50% calcium carbonate by weight. Becauseof the higher thermal conductivity using a composite cover material 125having a backing formed from a compound of polypropylene and calciumcarbonate comprising at least 50% calcium carbonate by weight, it isanticipated that the adhesive 135 will set faster, and thus, apparatus100 will operate at higher overall throughput than it would when using acomposite cover material 125 having a backing formed from a compound ofpolypropylene and calcium carbonate comprising more than 50%polypropylene.

The following tables presents illustrative paint rollers that will beused in the discussion below.

Cover Adhesive Strip Example A1  0/0% 10/0% 20/0% Example A2 10/0% 10/0%20/0%

The following table presents illustrative paint rollers that can beformed using the invention disclosed herein. The “Cover” column refersto the cover material 125 used, the “Adhesive” column refers to theadhesive 135 used and the “Strip” column refers to the strip 145 used inthe example. For each column, the entry reflects the thickness in mil,and the percentage of calcium carbonate (by weight) compounded withpolypropylene to form the component. The thickness in mil for the“Cover” column reflects the thickness of the layer 135 used to form thecomposite cover material 125—the “Cover” column entries showing athickness of 0 reflect the use of a cover material rather than acomposite cover material.

Cover Adhesive Strip Example B1 0/0% 10/60% 20/60% Example B2 10/0% 10/60% 20/60% Example B3 10/25% 10/60% 20/60%

Example A1 and B1, each make paint rollers of the same thickness,however, the characteristics of the paint roller B1 are substantiallyimproved when compared to those of A1. The B1 paint roller feels firmerand is of higher quality than the A1 paint roller. Moreover, the 30 milthick B1 paint roller uses only 40% of the polypropylene used tomanufacture the A1 paint roller (excluding any polypropylene in thecover material).

Similarly, Example A2 and B2, each make paint rollers of the samethickness, however, the characteristics of the paint roller B2 aresubstantially improved when compared to those of A2. The B2 paint rollerfeels firmer and is of higher quality than the A2 paint roller.Moreover, the 40 mil thick B2 paint roller uses only 55% of thepolypropylene used to make the A2 paint roller (excluding anypolypropylene in the cover material). In fact, the B1 paint rollercompares favorably to the A2 paint roller while using only as much as30% as much polypropylene.

Notably the B3 paint roller is the most superior of all of these examplerollers, and it uses less than half as much polypropylene as the A2roller, and just over half as much as the A1 roller.

Many other variations are possible. For example, it is not necessary touse both a compound adhesive and a strip formed from compoundingpolypropylene and calcium carbonate. In addition, it is not necessary touse a composite cover material formed from a compound ofpolypropylene/calcium carbonate. The use of (i) a compound strip, (ii)compound adhesive or (ii) composite cover material formed from acompound of polypropylene/calcium carbonate, will each produce astronger roller, with less polypropylene, than the use of same componentmade from non-compound polypropylene.

Returning now to FIG. 3, in an embodiment, strips 345, 348 comprisespolypropylene, and each have a thickness of between 10 mil and 40 mil.In an embodiment, strips 345, 348 are each approximately 10 mil, 15 mil,20 mil or 25 mil thick. In an embodiment, strips 345, 348 may be ofanother suitable thickness. It is not necessary that each of the strips345, 348 are the same thickness.

In an embodiment, at least one strip 345, 348 is made from apolypropylene/calcium carbonate compound comprising at least 50%, butnot more than 66% calcium carbonate by weight. In an embodiment, atleast one strip 345, 348 is made from a polypropylene/calcium carbonatecompound comprising approximately 60% calcium carbonate by weight. Astrip 345, 348 made from a polypropylene/calcium carbonate compoundcomprising at least 50% calcium carbonate by weight, is expected to havehigher thermal conductivity than a strip made from polypropylene alone,or than a strip made from a polypropylene/calcium carbonate compoundcomprising less than 50% calcium carbonate by weight. Because of thehigher thermal conductivity using at least one strip 345, 348 made froma compound of polypropylene and calcium carbonate comprising at least50% calcium carbonate by weight, it is anticipated that the adhesive 335will set faster, and thus, apparatus 100 will operate at higher overallthroughput than it would when using strips 345, 348 comprising more than50% polypropylene.

In an embodiment, adhesive 335 comprises polypropylene, and is appliedin a layer having a thickness of between 10 mil and 40 mil. In anembodiment, the layer of adhesive 335 is approximately 10 mil, 15 mil,20 mil or 25 mil thick. In an embodiment, the layer of adhesive 335 isanother suitable thickness.

In an embodiment, the adhesive 335 is made from a polypropylene/calciumcarbonate compound comprising at least 50%, but not more than 66%calcium carbonate by weight. In an embodiment, the adhesive 335 is madefrom a polypropylene/calcium carbonate compound comprising approximately60% calcium carbonate by weight. The adhesive 335 made from apolypropylene/calcium carbonate compound comprising at least 50% calciumcarbonate by weight, is expected to have higher thermal conductivitythan an adhesive made from polypropylene alone, or than an adhesive madefrom a polypropylene/calcium carbonate compound comprising less than 50%calcium carbonate by weight. Because of the higher thermal conductivityusing an adhesive 335 made from a compound of polypropylene and calciumcarbonate comprising at least 50% calcium carbonate by weight, it isanticipated that it will set faster, and thus, apparatus 100 willoperate at higher overall throughput than it would when using anadhesive 335 comprising more than 50% polypropylene.

In an embodiment, the backing of cover 325 comprises polypropylene, andthe backing comprising polypropylene is in a layer having a thickness ofbetween 10 mil and 40 mil. In an embodiment, the backing layer of thecomposite cover material 325 is approximately 10 mil, 15 mil, 20 mil or25 mil thick. In an embodiment, the backing of the composite covermaterial 325 is another suitable thickness.

In an embodiment, the backing of the composite cover material 325 isformed from a polypropylene/calcium carbonate compound comprising atleast 50%, but not more than 66% calcium carbonate by weight. In anembodiment, the backing of the composite cover material 325 is formedfrom a polypropylene/calcium carbonate compound comprising approximately60% calcium carbonate by weight. The backing of the composite covermaterial 325 formed from a polypropylene/calcium carbonate compoundcomprising at least 50% calcium carbonate by weight, is expected to havehigher thermal conductivity than a backing made from polypropylenealone, or than a backing made from a polypropylene/calcium carbonatecompound comprising less than 50% calcium carbonate by weight. Becauseof the higher thermal conductivity using a composite cover material 325having a backing formed from a compound of polypropylene and calciumcarbonate comprising at least 50% calcium carbonate by weight, it isanticipated that the adhesive 335 will set faster, and thus, apparatus100 will operate at higher overall throughput than it would when using acomposite cover material 325 having a backing formed from a compound ofpolypropylene and calcium carbonate comprising more than 50%polypropylene.

The following tables presents illustrative paint rollers that will beused in the discussion below.

Cover Adhesive Strip 1 Strip 2 Example C1  0/0% 10/0% 10/0% 10/0%Example C2 10/0% 10/0% 10/0% 10/0% Example C3 10/0% 10/0% 20/0% 20/0%Example C4  0/0% 10/0% 20/0% 20/0%

The following table presents illustrative paint rollers that can beformed using the invention disclosed herein. The “Cover” column refersto the cover material 325 used, the “Adhesive” column refers to theadhesive 335 used, the “Strip 1” column refers to the strip 345 used andthe “Strip 2” column refers to the strip 348 used in the example. Asabove, for each column, the entry reflects the thickness in mil, and thepercentage of calcium carbonate (by weight) compounded withpolypropylene to form the component. The thickness in mil for the“Cover” column reflects the thickness of the layer 335 used to form thecomposite cover material 325—the “Cover” column entries showing athickness of 0 reflect the use of a cover material rather than acomposite cover material.

Cover Adhesive Strip 1 Strip 2 Example D1 0/0% 10/56% 10/60% 10/60%Example D2 10/0%  10/56% 10/60% 10/60% Example D3 10/25% 10/56% 10/60%10/60% Example D4 10/25% 10/56% 20/60% 20/60%

Example C1 and D1, each make paint rollers of the same thickness,however, the characteristics of the paint roller D1 are substantiallyimproved when compared to those of C1. The D1 paint roller feels firmerand is of higher quality than the C1 paint roller. Moreover, the 40 milthick core of the D1 paint roller uses only 42% of the polypropyleneused to manufacture the C1 paint roller (excluding any polypropylene inthe cover material).

Example D2 forms a paint roller with very good properties and firmness.This roller compares favorably to Example D1 due to its extra 10 milthickness. Moreover, Example D2 compare favorably not only to ExampleC1, but to Example C2 having a core of the same thickness (50 mil), andeven to Example C3, despite Example C3 having a core of 70 mil and usingsubstantially more than twice as much polypropylene. Example D3 makes aneven better paint roller, while Example D4 makes an excellent qualitypaint roller. Notably, while Example D4 is the same core thickness asexample C3, it uses only about 46% as much polypropylene.

As above, many other variations are possible. For example, it is notnecessary to use both a compound adhesive and a strip formed fromcompounding polypropylene and calcium carbonate. Moreover, it is notnecessary to form both strips from a compound adhesive. In addition, itis not necessary to use a composite cover material formed from acompound of polypropylene/calcium carbonate. The use of (i) a compoundstrip, (ii) compound adhesive or (ii) composite cover material formedfrom a compound of polypropylene/calcium carbonate, will each produce astronger roller, with less polypropylene, than the use of same componentmade from non-compound polypropylene.

Further, it has been observed that the two-strip 60 mil core roller ofExample C4 provides approximately the same qualities as the singlestrip, 40 mil core roller of Example A2, while the latter roller usesonly about 37% as much polypropylene. Also, notably, the two-strip 50mil core Example D2 provides a much stronger roller than the two-strip60 mil core roller made according to Example C4.

Returning to FIG. 4, in an embodiment, one or both of the strips 445,448 can be made from a compound of polypropylene and calcium carbonatehaving at least 50%, but not more than about 66% calcium carbonate byweight. Similarly, in an embodiment the cover 415 may having a backingmade of a compound of polypropylene and calcium carbonate having atleast 50% but not more than 66% calcium carbonate by weight. Asdiscussed above, the percentage of calcium carbonate used in thecompound forming the strips 448, 445 and the cover 415 backing may bethe same, or may differ from one-another.

In an embodiment, the strips 445, 448 are made from a compound ofpolypropylene and calcium carbonate having approximately 60% calciumcarbonate, and the cover 415 has a backing made of a compound of 105 MFIpolypropylene and non-refined calcium carbonate having approximately 25%calcium carbonate by weight.

Returning to FIG. 5 Apparatus 500 may be operated according to thepresent invention using a preformed core 540 made of a compound ofpolypropylene and calcium carbonate having at least 50%, but not morethan 66% calcium carbonate by weight; and/or using a cover 520 having abacking made of a compound of polypropylene and calcium carbonate havingbetween 5% and 66% calcium carbonate by weight. When more than onecomponent is made of a compound of polypropylene and calcium carbonate,the percentage of calcium carbonate used in the compound forming thecore 540 and the cover 520 backing may be the same, or may differ fromone-another. In an embodiment, the core 540 is made of a compound ofpolypropylene and calcium carbonate comprising approximately 60% calciumcarbonate by weight, and the cover backing is made of a compound ofpolypropylene and calcium carbonate comprising approximately 25% calciumcarbonate by weight.

As discussed above Variation in the amount of calcium carbonate arewithin the scope of the invention, and thus, it will be apparent to oneof skill in the art that to some degree thermal conductivity can becontrolled, or a desired thermal conductivity or range of thermalconductivity can be achieved by varying the percentage of calciumcarbonate in one or more of the compounds. It will be apparent to one ofskill in the art that to some degree, stiffness can be controlled, or adesired stiffness or range of stiffness can be achieved by varying thepercentage of calcium carbonate in these compounds as well.

It is possible, without departing from the invention, to use a compoundof polypropylene and calcium carbonate having between 50% and 60%calcium carbonate by weight in lieu of polypropylene in making paintrollers. In light of this disclosure, other methods for the manufactureof the same will be apparent to persons of skill in the art.

Benefits of certain embodiments of the instant invention include:control of thermal conductivity in the component materials leading tofaster throughput and/or faster set times; and control of materialcharacteristics such as stiffness for manufacture of harder, moreexpensive paint rollers.

The above embodiments and preferences are illustrative of the presentinvention. It is neither necessary, nor intended for this patent tooutline or define every possible combination or embodiment. The inventorhas disclosed sufficient information to permit one skilled in the art topractice at least one embodiment of the invention, and has disclosed theways the inventor now believes are the best ways to practice theinvention. The above description and drawings are merely illustrative ofthe present invention and that changes in components, structure andprocedure are possible without departing from the scope of the presentinvention as defined in the following claims. Thus, while the inventionhas been particularly shown and described with reference to embodimentsthereof, it will be understood by those skilled in the art that variouschanges in form and details may be made therein without departing fromthe spirit and scope of the invention. The above embodiments areillustrative of the present invention. It is neither necessary, norintended for this patent to outline or define every possible combinationor embodiment.

1. A method of making a paint roller comprising the steps of: helicallywinding a strip of material around a mandrel so as to form a helicallywound strip; advancing the wound strip along the mandrel; extruding apolypropylene-based compound to form a smoothly flowing layer ofadhesive, the polypropylene-based compound comprising (i) at least 50%but not more than 66% calcium carbonate by weight, and (ii) apolypropylene resin; applying the layer of adhesive onto an outersurface of the wound strip; helically wrapping a strip of cover materialabout the wound strip and over the layer of adhesive; and, allowing theadhesive to cool, thereby bonding the strip of cover material to thewound strip.
 2. A method for continuously producing a multi-striplaminate paint roller comprising the steps of: helically advancing aninner strip and an outer strip of material about a mandrel in offsetrelation; extruding a polypropylene-based compound to form a smoothlyflowing layer of adhesive, the polypropylene-based compound comprising(i) at least 50% but not more than 66% calcium carbonate by weight, and(ii) a polypropylene resin; applying the layer of adhesive between thetwo strips and on the outer surface of the outer strip; prior topermitting the adhesive material to harden and set, wrapping a coveraround the outer strip and applying a compressing force upon the coverurging the cover and the two strips toward the mandrel; and, allowingthe adhesive to harden and set, thereby creating the multi-striplaminated paint roller.
 3. A method of making a paint roller comprisingthe steps of: Extruding a polypropylene-based compound to form asmoothly flowing layer of adhesive, the polypropylene-based compoundcomprising (i) at least 50% but not more than 66% calcium carbonate byweight, and (ii) a polypropylene resin; applying the adhesive between acover material and one or more other materials, which, with theadhesive, make up the paint roller core; permitting the adhesive toharden and set, thereby creating the paint roller.
 4. A method of makinga laminated paint roller comprising the steps of: helically winding aninner strip of thermoplastic material around a mandrel so as to form ahelically wound inner strip, the inner strip having an inner surface andan outer surface; helically winding a second strip of thermoplasticmaterial around a mandrel in offset relation to the inner strip, so asto form a helically wound second strip, the second strip having an innersurface and an outer surface; advancing the wound inner and secondstrips along the mandrel; extruding a polypropylene-based compound toform a smoothly flowing layer of adhesive, the polypropylene-basedcompound comprising (i) at least 50% but not more than 66% calciumcarbonate by weight, and (ii) a polypropylene resin; applying the layerof adhesive onto the outer surface of the wound inner strip and theouter surface of the wound second strip; wrapping a strip of compositecover material about the wound second strip and over the layer ofadhesive applied to the wound second strip, the composite cover materialhaving an inner surface and an outer surface, the outer surface of thecover material comprising a pile fabric, and the inner surfacecomprising a smooth, generally non-porous backing comprisingpolypropylene; applying a compressive force from without the compositecover material to urge the composite cover material, the layer ofadhesive, and the inner and second strips together, thereby laminatingthe inner surface of the composite cover material to the outer surfaceof the second strip and laminating the inner surface of the second stripto the outer surface of the inner strip; and, allowing the adhesive tocool and set.
 5. A method of making a laminated paint roller comprisingthe steps of: helically winding a strip of thermoplastic material arounda mandrel so as to form a helically wound strip, the strip having aninner surface and an outer surface; advancing the wound strip along themandrel; extruding a polypropylene-based compound to form a layer ofadhesive, the polypropylene-based compound comprising (i) at least 50%but not more than 66% calcium carbonate by weight, and (ii) apolypropylene resin; applying the layer of adhesive onto the outersurface of the wound strip; wrapping a strip of composite cover materialabout the wound strip and over the layer of adhesive applied to thewound strip, the composite cover material having an inner surface and anouter surface, the outer surface of the composite cover materialcomprising a pile fabric, and the inner surface comprising a smooth,generally non-porous backing comprising polypropylene; applying acompressive force from without the composite cover material to urge thecomposite cover material, the layer of adhesive and strip together,thereby laminating the inner surface of the composite cover material tothe outer surface of the strip; and allowing the adhesive to cool andset.